It has been known for more than a century that electrons accelerated towards and striking an anode at high energies will cause a cathodoluminescent phosphor on the anode to emit light. When used with tightly focused electron beams and magnetic or electrostatic deflection systems, this method of producing light from phosphors has been widely used in display devices for generations. It has been proposed to use an electron beam to excite phosphors for general room lighting.
There are many differences in detail between the requirements for general room lighting devices and display devices.
A prior anode fabrication method for monochromatic phosphor screens is as follows:                a. An optional transparent electrode layer is applied to a face of a glass envelope.        b. Phosphor slurry is prepared combining phosphor powder (which may contain a blend of luminescent compounds to give emitted light desired spectral characteristics), potassium silicate, water, and small amounts of other chemicals including electrolytes.        c. The slurry is poured into the glass envelope and allowed to settle.        d. After phosphor settles from the slurry, the remaining liquid is removed.        e. Phosphor left on the face of the glass envelope is dried to a solid coating        f. The phosphor is baked to dry and harden the phosphor coating.        g. Water “pre-wet,” containing surfactants, is introduced to the envelope and poured out, leaving a slight residue of the pre-wet solution on the rough surface of the phosphor layer and filling tiny cavities thereon.        h. Immediately, a lacquer is applied over the phosphor+pre-wet composite. The lacquer and residual pre-wet is allowed to dry. The result is a smooth surface of lacquer.        i. A thin, conductive, reflective, layer of metal is deposited on the surface of the lacquer; typically this is done by placing a pellet of aluminum on a surface that is then heated by a filament.        
Electron guns are commonly used for generating an electron beam for use in Cathode Ray Tubes (CRTs), electron microscopes, x-ray tubes, and other applications. In common use, the electron gun or electron source has electron optics for beam control, typically forming a narrow beam, and in order to stabilize emission. Each electron source has at least one cathode.
In every basic free electron-source lamp, regardless of the type of electron source (thermionic cathode, cold cathode, field-emission cathode), it is required to have an anode contact that allows return of current from the anode. These contacts are typically spring-formed contacts that extend into a glass envelope of the lamp to contact the anode layer.
FIG. 13 shows part of a prior-art cathode ray tube 6 having an electron source 12 and a snubber support tube 10 with independently sprung anode contacts 14 that contact an anode layer 16 within a glass enclosure 8. FIG. 14 shows a front view of snubber tube 10 of FIG. 13 illustrating positions of the three independently sprung contacts 14, as typically used in the industry. Snubber 10 is typically tubular such that contacts 14 are symmetrically attached around the tube. Tube 10 imparts a force to each contact 14 to ensure contact between contacts 14 and anode layer 16.